industrial chemistry Flashcards

1
Q

contributions of chemistry to society

A

1- provides chemicals, pharmaceutical, fuels, medicines, agrochemicals, etc

2- provides materials such as plastics, semi-conductors, synthetic fibres, etc

3- provides stable well paid employment and contributes to knowledge economy

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2
Q

james muspratt

A

nationality: Irish
field: chemist, industrialist

“father of the modern chemical industry”

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3
Q

principles of industrial chemistry

A

batch process
continuous process
semi-continuous process

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4
Q

batch process

A

reactants/feedstock are allowed to react for a fixed time with each other inside a vessel known as a batch reactor, under controlled conditions of temp and pressure. When reaction complete, product is isolated

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5
Q

continuous process

A

feedstock continually fed in at one end of plant + product continually removed at other end. All case studies are continuous

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6
Q

semi-continuous process

A

combination of batch process + continuous process. First stage involves batch process to make product, second stage involves continuous process where product is purified using feed from various batch reactors

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7
Q

batch process advantages

A
  • low capital costs
  • easier to cater for slow reactions
  • versatile (usable for diff processes)
  • usable for trial runs
  • suit seasonal products
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8
Q

batch process disadvantages

A
  • time consuming + labour intensive
  • contamination more likely
  • difficult to control exothermic reactions
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9
Q

continuous process advantages

A
  • low risk of contamination since only one product is being made
  • long periods of use w/o stopping for maintenance
  • suitable for large scale production
  • long periods between maintenance
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10
Q

continuous process disadvantages

A
  • high capital costs
  • less flexibility as plant is tailor-made for a specific product
  • not cost effective unless run at full capacity
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11
Q

characteristics of an industrial chemical process

A

raw materials: limestone from local quarry and seawater from Boyne estuary

feedstock: calcium hydroxide and purified seawater

reactants are called feedstock and produced from raw materials

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12
Q

reaction rate

A

-main reaction is fast
MgCl₂ + Ca(Oh)₂ –> Mg(OH)₂ + CaCl₂

  • to slow process down for formation of large crystals, incoming seawater is diluted with spent seawater
  • reaction mixture is seeded with Mg(OH)₂. High temp of 900°C speeds up loss of water from MgO

Mg(OH)₂ –> MgO + H₂O

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13
Q

products

A

co-products
by-products
product yield

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14
Q

co-products

A

other products made along with main product - in this case, CaCl₂

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15
Q

by-products

A

products made from side reactions, which reduce yield of main product - no by-products in this case

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16
Q

product yeild

A

2g MgO from a litre of seawater

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17
Q

waste disposal and effluent control

A
  • dust removed by electrostatic precipitators
  • gases scrubbed to remove SOx + grit
  • used seawater contains Ca(OH)₂ which is alkaline + has to be neutralised to reduce pH
  • filtered to remove suspended solids before being released back to sea
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18
Q

quality control

A

analysis of all reactants + products are carried out at every stage. Acid-base titrations used + x-ray fluorescence is an instrumentation technique used to test purity of MgO crystals

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19
Q

safety

A
  • ongoing health + safety training for staff on site

- personal protective equipment (ppe) - helmets, boots, goggles, ear plugs, clothing

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20
Q

costs

A

fixed costs

variable costs

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21
Q

fixed costs

A
  • those that have to paid regardless of rate of production of plant
  • labour, plant depreciation, repayment of loans etc.
22
Q

variable costs

A
  • depend directly on rate of production of plant
  • costs of raw materials, costs of effluent treatment and disposal, distribution costs, plant maintenance, administration, etc
23
Q

how to reduce costs

A

recycling + using waste gases for heating

24
Q

site location

A
  • plentiful supply of seawater from Boyne estuary
  • site located near local limestone quarry w/ good road + rail network for easy transport
  • highly skilled workforce available
  • site had suitable equipment already as it was previously a cement factory
25
Q

construction materials

A

large concrete silos.
kilns and furnaces lined w/ refractory bricks
many buildings made of steel w/ outer cladding
materials that are un-reactive + resist corrosion used

26
Q

case study

A

Premier Periclase

27
Q

Premier Periclase - manufacture

A

manufacture of magnesium oxide is carried out by Premier Percilase in Drogheda, Co. Louth

28
Q

Premier Periclase - process

A
  • a continuous process.
  • MgO occurs in the mineral periclase. Has high melting point 2800°C + used to make refractory bricks, which are heat resistant for lining furnaces
  • MgO powder made into pellets + briquettes
29
Q

Premier Periclase - raw materials

A

limestone CaCO₃

sea water

30
Q

Premier Periclase - feedstock

A

calcium hydroxide Ca(OH)₂

purified seawater

31
Q

Premier Periclase - preparation of raw materials

A

seawater is degassed to remove dissolved gases + filtered to remove solids such as sand + silt hence purifying seawater

32
Q

Premier Periclase - preparation of raw materials equations

A

CaCo₃ (limestone) —(roasting)—> CaO (lime) + CO₂

CaO (lime) + H₂O —> Ca(OH)₂ (limewater)

33
Q

Premier Periclase - main reaction

A

Ca(OH)₂ + MgCl₂ –> CaCl₂ + Mg(OH)₂ –(heat)–> MgO (used to make refractory bricks for lining furnaces)

34
Q

main reaction/(last two stages of the process) balanced equation

A

MgCl₂ + Ca(Oh)₂ –> Mg(OH)₂ + CaCl₂

Mg(OH)₂ –> MgO + H₂O

35
Q

use of magnesium oxide produced

A
  • refractory material
  • heat resistance material
  • fire-bricks
36
Q

substance whose concentration is higher in seawater effluence than it is in seawater feedstock

A

calcium chloride (CaCl₂)

37
Q

measures taken by companies to avoid ecological damage to their surroundings

A
  • control dust
  • constrol dust
  • control temp/pH of water returned to the sea
  • waste water pumped out to sea
38
Q

describe a chemical method for removing acidic gases from industrial chimney waste

A

-scrubbing with limestone

39
Q

Feedstock

A

materials (reagents, chemicals, substances) used in the reaction / used to make the industrial product

40
Q

Raw materials

A

used to produce feedstock

41
Q

Why are glass and steel widely used as materials for the reaction vessels in the chemical industry?

A
  • they are chemically unreactive
  • hard wearing
  • easy to clean
  • can be moulded
  • cheap
42
Q

why was periclase located where it is located?

A

just list the site location flashcard

43
Q

what happens in the scrubbing of waste acidic gases in industry?

A

-lime/limstone reacts with gases

44
Q

explain whether fractional distillation of air is a continuous or a batch process

A
  • continuous
  • air goes in at one end + product comes out at the other in a continuous manner
  • air is cooled + fractioned continuously
45
Q

co-products of the fractional distillation of air

A
  • liquid nitrogen
  • neon
  • argon
  • krypton
46
Q

use of co-products of the fractional distillation of air

A
  • nitrogen: inert atmosphere, freezing of food
  • neon: inert atmosphere, lighting, tv tubes
  • argon: inert atmosphere, lighting
47
Q

write a balanced equation for the reaction that occurs when sulfur dioxide from industrial gaseous emissions dissolves in water

A

SO₂ + H₂O –> H₂SO₃

48
Q

how the raw materials are treated before they become the feedstock for the manufacturing process

A
  • limestone: crushed, washed, calcined (heated to quicklime), slakes (water added to form slaked lime)
  • sea water: acidified, degassed (CO₂ removed), clarified (solids settle)
49
Q

name one product which if discharged could cause pollution

A
  • dust
  • lime
  • magnesium oxide
  • suspended solids (calcium hydroxide)
50
Q

most important use of the main product + what makes it particularly suitable for the use

A
  • heat-resistant material/furnace lining

- very high melting point, insulating

51
Q

how is oxygen gas produced industrially?

A
  • liquefaction
  • fractional distillation
  • using diffusion
  • electrolysis of acidified water
52
Q

outline processes carried out in manufacture of main product, incl equations

A
  • lime (calc hydroxide) produced from limestone
  • CaCO₃ –? CaO + CO₂
  • CaO (quicklime) with water gives Ca(OH)₂ (lime)
  • CaO + H₂O –> Ca(OH)₂
  • reaction with MgCl₂ in seawater
  • magnesium hydroxide heated to give magnesium oxide
  • Mg(OH)₂ –> MgO + H₂O

-Ca(OH)₂ + MgCl₂ –> Mg(OH)₂ + CaCl₂